In the art solid, polymeric electrolytes (also said "ionic conductor polymers") are known, which are constituted by a solid solution of an ionic compound dissolved in a solid, plastic, macromolecular material, with the latter being the product of polymerization of monomers containing at least one heteroatom, in particular oxygen. Usually, said macromolecular material is polyethyleneoxide, or another polyether, such as, e.g, disclosed in U.S. Pat. No. 4,471,037; French patents 2,523,769 and 2,568,574; and in European patent 13,037.
The problems arising in connection with such solid, polymeric electrolytes generally derive from their poor mechanical characteristics, and from their low dimensional stability. Another drawback consists in that they usually only show a satisfactory ionic conductivity at temperatures higher than room temperature values. All the above drawbacks result in the solid, polymeric electrolytes known from the prior art being not very interesting for practical uses.
The purpose of the present invention is of overcoming the drawbacks which affect the prior art, as briefly mentioned above. More particularly, the present Applicant found, according to the instant finding, that the product of copolymerization of a monoepoxide and a diepoxide, selected from within particular classes of epoxy compounds, can be easily converted into solid, polymeric electrolytes and that these latter are endowed with good mechanical characteristics and good ionic conductivity also at relatively low temperature.